Evaluation of the blood-brain barrier based on the functional analysis of transporters using newly developed techniques.

在目前的研究中，我们研究了脑毛细血管内皮细胞中具有血脑屏障功能的膜转运体。通过这项研究，我们发现了三个新的在血脑屏障表达的转运蛋白，其中一个是单羧酸转运蛋白MGT1，它负责摄取和/或排出有机弱酸，如乳酸、丙酮酸和苯甲酸。第二个转运蛋白是中性氨基酸转运蛋白LAT1和LAT2。这两种氨基酸转运体的作用是摄取相对亲水性和大分子的氨基酸，包括亮氨酸、酪氨酸和苯丙氨酸。这些对L多巴的脑部涂抹也很重要，这对培金森症有效。第三个转运蛋白是OCTN2，被称为肉碱/有机阳离子转运蛋白。OCTN_2是一种钠依赖的肉碱转运体，作用于大脑摄取乙酰基-L-Carhitirie，有望用于艾哲…更多的是伊梅尔氏症。另一方面，脑外流转运体保护大脑免受有毒的外源生物的伤害。本研究以H1-受体拮抗剂依巴斯汀、凯巴斯汀和氟喹诺酮类药物格列帕沙星为模型药物。一般来说，氟喹诺酮类和H1拮抗剂会出现癫痫和镇静等不良反应，而本研究中研究的药物没有这种不良反应。我们预计，这些药物可能没有足够的渗透性通过血脑屏障，导致向大脑的传递不足，从而造成不利的不良反应。对这些药物的血脑屏障转运的各种研究表明，至少存在两种类型的脑外排转运体，包括P-糖蛋白和阴离子交换转运体，其分子鉴定尚待成功。所有这些研究都是利用各种血脑屏障转运技术进行的。特别是，从大鼠脑毛细血管内皮细胞中新开发的RBEC1细胞系对本研究的成功是有用的。此外，我们还挑战了血管内皮细胞和星形胶质细胞的共培养，以模拟体内的血脑屏障。虽然我们部分成功地制备了体外血脑屏障模型，但要想建立高效、完整的血脑屏障转运模型，还需要进一步的改进。较少

In the present study, we studied membrane transporters equippecd, in the brain capillary endothelial cells that are functional as the blood-brain barrier. Through this study, we found three new transporters that are expressed at the blood-brain barrier.One of those transporters are monocarboxylic acid transporter MGT1, which tworks for uptake and/or efflux organic weak acids such as lactic acid, pyruvic acid and benzoic acid. The second transporter is neutral amino acid transporters LAT1 and LAT2. These two amino acid transporters work for the uptake of amino acids that are relatively hydrdphpbic and large molecules, including leucine, tyrosine and phenylalanine. These are also important for the brain livery of L-DOPA that is effective for perkinsonism. The third transporter is OCTN2that is callsified as the carnitine/organic cation transporter. OCTN2 is a Na^+-dependent carnitine transporter and works for the brain uptake of acetyl-L-carhitirie that is expected to be useful for Aitzhe … More imer's disease. On the other hand, brain efflux transporters that protect brain from the toxic xenobiotics. As the model drugs, H1-antagonist, ebastine and carebasitine and fluoroquinolone, grepafloxacine, was used in the present study. Generally, fluoroquinolonesand H1 antagonists exhibit adverse effects such as epilepsy and sedative effects, while the drugs studied in the present study do not show such adverse effects. We expected that these drugs might not have enough permeability across the blood-brain barrier, resulting in the insufficient delivery to the brain to cause unfavorable adverse effects. Varipus Kinds of studies on the BBB transport of these drugs demonstrated that there are at least two types of brain efflux transporters, including p-glycoproteih and anion exchange transporter, of which molecular identification remains to be succeeded.All of these studies were performed by using various BBB-transport techniques. Especially, newly developed cell line RBEC1 that were derived from rat brain capillary endothelial cells was useful for the success of the present study. Furthermore, we challenged of the coculture of the endothelial cells and astrocytes in order to mimic the in vivo BBB. Although we partly succeeded to prepare the in vitro BBB model, further improvement will be essential for the efficient and complete model for the evaluation of blood-brain barrier transport. Less